#include <stdio.h>
float f(float x);
float a3, a2, a1, a0;
int main()
{
    float a, b;
    scanf("%f %f %f %f", &a3, &a2, &a1, &a0);
    scanf("%f %f", &a, &b);
    float left, mid, right;
    left = a;
    right = b;
    while (left <= right - 0.001 && f(left) * f(right) <= 0)
    {
        if (f(left) == 0)
        {
            printf("%.2f", &left);
            return 0;
        }
        if (f(right) == 0)
        {
            printf("%.2f", right);
            return 0;
        }
        mid = (left + right) / 2;
        if (f(mid) * f(left) > 0)
        {
            left = mid;
        }
        else
        {
            right = mid;
        }
    }
    printf("%.2f", mid);
    return 0;
}
float f(float x)
{
    float result;
    result = a3 * x * x * x + a2 * x * x + a1 * x + a0;
    return result;
}
